This invention relates to an article of manufacture characteristically in the form of an elongated hollow cylinder having a continuous side wall with a narrow weakened wall segment substantially along the length of the cylinder for access to the interior thereof by fracturing the side wall along the weakened wall segment. Such an article is used to protect a cable while fed into an underground conduit, as a varmint guard for a tree trunk or overhead cable, as a protective enclosure for a wire harness or existing cable, as a removable form for concrete or as a protective cover for a cable splice.
In the placement of underground cables, particularly telephone communication cable and electric utility cable, certain procedures and precautions are necessary to protect the cable from damage during the placement operation. It is well known in the art to use a metal feeder tube for protection and guidance of the cable while fed from a supply reel to an underground conduit. Recent technology advancements to the manufacture and placement of cables have been about the concept of joining the conductors of the cable at one end with connectors prior to the placement of the cable so that the laborious and time-consuming operations required for connecting together the ends of two cables in a single manhole are reduced to a minimum. Because of the increased cost of such cable, special facilities are needed and adequate precautions must be taken to prevent damage to the cable, particularly the sheathing thereof. Typically, for example, a telephone communication cable is about 31/2 inches in diameter and the end equipped with connectors may be as large as 11 inches in diameter. Thus, conventional feeder tubes are unsuitable because it is impossible to pass the tube onto or from the end of the cable where the connectors are attached to the conductors. A conventional feeder tube had been cut longitudinally and held together by hinges at one side and latches at the other side. However, such modifications to a metal feeder tube are not adequate solutions to the problem. Alignment between the split tube parts cannot be maintained because of the weight of the feeder tube and the forces imposed upon the feeder tube during the cable pulling operation. As a result, the sheathing of the cable is damaged due to cuts by protruding edges of misaligned tube halves. Because of the forces involved, the cable must be fed very slowly through a divided feeder tube which increases an already-costly placement and handling operation of the cable. The weight of a metal feeder tube is detrimental because support rigging is necessary to prevent unwanted deflections of the cable by the feeder tube.
The article of manufacture according to the present invention is useful not only for cable placement where the need to strip the feed tube from the cable laterally thereof is achieved by fracturing the weakened wall segment, but also in other fields where there is a need to pass a tube onto an article after fracturing the weakened wall segment to form a protective guard. The tube of the present invention is particularly useful to protect the truck of tree saplings against attack by varmints or other animals. The tube is also useful to protect a wire harness having connectors at both ends; for installing a conduit over an existing cable; to provide a covering for protection of a segment of a cable wherein a large diameter splice exists; and for use as a removable form to cast concrete for the production of a fence post or the like.
The weakened side wall segment in the article of manufacture according to the present invention not only eliminates the need for a knife-edge or machine to longitudinally sever the side wall, but also permits severing the side wall at any convenient place, including at the job site and under difficult working conditions. Even when the article includes a transverse rib configuration, the weakened side wall segment is equally effective to form the parting line in the side wall. In the past, a plastic tube with transverse ribs was difficult to sever for producing the parting line even when specially designed machinery was utilized.